Polytone Mini Brute II - Power switch

[Djangology]

Those caps look very ike the original caps to me -although I suppose it's possible they have been replaced by the same make. You can tell, because the original caps have a screw fitting underneath that is unusual these days.

I'm admittedly baised, as I had one cap explode and damage several other components, which was expensive to fix - but it's quite possible yours might still be OK.
I see it as insurance! You could see if the caps get warm after 20 minutes or so; if they do, comsider changing them. Or, if the amp hums at audible volume.

Thank you very much! I will check the caps like you suggest.

[Mick-7]

You could see if the caps get warm after 20 minutes or so; if they do, comsider changing them. Or, if the amp hums at audible volume.

My Polytone 102 does hum, it's quite annoying, it has since I bought it earlier this year (but everything works otherwise), is that the most likely reason? I had a local amp tech look at it but he had an aversion to working on it (maybe it's the death cap? ). I need to find another tech.

[Franz 1997]

It's definitely a likely reason, although the Polytones I've owned have all had a slight background hum, even new ones. But if it's more than that, the first thing to check is the big power supply capacitors. They dry up over the decades, and become less efficient at filtering out mains hum, until they give up. If the caps are getting hot, they need to be changed. Bad grounds are another possible cause.

Yes unfortunately many techs won't work on polytones. They are very simple amps, but something of a rat's nest visually, and tricky to bias correctly. If you can find a tech, the schematics are available online, and some service manuals.

[vintagelove]

My Polytone 102 does hum, it's quite annoying, it has since I bought it earlier this year (but everything works otherwise), is that the most likely reason? I had a local amp tech look at it but he had an aversion to working on it (maybe it's the death cap? ). I need to find another tech.

Hello, an easy cheap fix for this is to put a volume pot between the preamp output and the power amp input. Just knocking a few db down really cleans up the noise floor (a good working polytone has a very quiet power amp).

This is especially necessary for the baby brute. The transformer induces noise into the preamp because they're so close together.

Sure, you lose a little volume, but it's not like most of us are playing with our Polys on 10, and if you ever do need full volume, just turn it up.

Hope that helps.